New strategy for removing biogenic interferences from mineral oil aromatic hydrocarbons in vegetable oils

Wednesday, May 1, 2024

11:35 AM – 11:55 AM EDT

Room: 524b

Presenting Author(s)

Aleksandra Gorska, Ir (she/her/hers)

Teaching Assistant and PhD candidate
Gembloux Agro-Bio Tech (University of Liège)
Gembloux, Namur, Belgium

Co-Author(s)

Grégory Bauwens, MA

PhD student
University of Liège
Gembloux, Namur, Belgium
Giorgia Purcaro, PhD (she/her/hers)

Analytical Chemistry Professor
University of Liège
Gembloux, Namur, Belgium

Abstract: Quantification of mineral oil aromatic hydrocarbons (MOAH) in vegetable oils is known to be challenging due to the coelution of biogenic interferences during chromatographic separation. Currently, the purification of those interferences is performed through epoxidation – a chemical reaction which adds an epoxy group at double bond positions, making the compounds more polar, therefore changing their elution properties during chromatographic separation. However, it is known that epoxidation may cause MOAH losses which lead to potential quantification biases, and may fail to remove all kinds of interferences – some of them being more inert to the reaction.

This work aims at presenting a new purification strategy which is not based upon a chemical reaction anymore, but rather upon a simple high performance liquid chromatography (HPLC) separation using the same HPLC system and solvents as required for mineral oil analysis. The performances of the method in terms of quantification accuracy and efficiency of interfering compounds’ removal are discussed for different vegetable oils, such as palm, coconut, olive and sunflower oil. It is shown that, compared to the conventional purification methods, the newly developed method yields in much lower MOAH quantification. Specifically, it achieves a much lower quantification bias of around 5% as opposed to over 40% when using epoxidation. The method exhibits a mean recovery of 68% (± 4%) for 17 standard compounds, including MOAH internal standards and polycyclic aromatic hydrocarbons. Additionally, it effectively eliminates common biogenic interferences such as squalene and carotenoids from the samples.